Java：如何使用Thread.join

使用这样的东西：

public void executeMultiThread(int numThreads)   throws Exception{    List threads = new ArrayList();    for (int i = 0; i < numThreads; i++)    {        Thread t = new Thread(new Runnable()        { public void run() {     // do your work }        });        // System.out.println("STARTING: " + t);        t.start();        threads.add(t);    }    for (int i = 0; i < threads.size(); i++)    {        // Big number to wait so this can be debugged        // System.out.println("JOINING: " + threads.get(i));        ((Thread)threads.get(i)).join(1000000);    }